Recording system



July 23, 1935. J. H. HAMMOND, JR

RECORDING SYSTEM Filed April 6, 1953 VzZ7T4O ATTORN EYS l/ii.

llLLli'flUN l- Patented July 23, 1935 UNITED STATES scam?! H.

PATENT OFFICE RECORDING SYSTEM John Hays Hammond, Jr., Gloucester, Mass.

Application April 6, 1933, Serial No. 664,718

12 Claims.

This invention relates to sound recording systems, and more particularlyto a monitoring-systern f gr nse' in the recording oforchestralselections.

The invention provides means for permitting the orchestra leader ormonitor to hear the music as it is being recorded, and at the same timeto hear the scratch noises as they will sound when the record is beingreproduced. The invention accordingly enables the leader or monitor tocontrol the recording so that the sound level of the recorded music willat no time fall below the scratch noise level, whereby a record isproduced, free from the disagreeable effect of the scratch noise whichtends to predominate at times of pianissimo in the music.

The invention also consists in certain new and original features ofconstruction and combinations of parts hereinafter set forth andclaimed.

Although the novel features which are believed to be characteristic ofthis invention will be particularly pointed out in the claims appendedhereto, the invention itself, as to its objects and advantages, the modeof its operation and the manner of its organization may be betterunderstood by referring to the following description taken in connectionwith the accompanying drawing forming a part thereof, in which thesingle figure illustrates diagrammatically a system embodying thepresent invention.

In the following description and in the claims, parts will be identifiedby specific names for convenience, but they are intended to be asgeneric in their application to similar parts as the art will permit.

Referring more particularly to the drawing, a microphone I0 is adaptedto be suspended at a suitable distance in front of the orchestra orother source of sound to be recorded and is connected through atransformer H to the input circuit of a space discharge amplifier l2.The output circuit of the amplifier |2 includes the primary of atransformer l3, the secondary of which is connected across apotentiometer I4, the adjustable contact l of which is connected to thegrid of a. second space discharge amplifier I6. The output circuit ofthis amplifier |6 includes the primary of a transformer H, the secondaryof which is connected in the input circuit of a push-pull amplifier l8.The output of this amplifier H3 includes the primary of a transformer l9which is provided with two secondary windings ISa and The secondary |9ais connected to a phonograph engraving mechanism 2| which is providedwith an engraving tool 22 for engravin a master record 23. This recordis carried on the turn table 24 of a phonograph driving mechanism 25 ofusual construction. The engraving mechanism 2| is mounted on the end ofan arm 26,

pivoted to a shaft 21, which is slowly rotated by the phonograph drivingmechanism 25, so that the engraving tool 22 cuts a spiral record grooveon the upper surface of the master record 23 in Well known manner.

The secondary |9b is connected across a potentiometer 3 the adjustablecontact 32 of which is connected to the grid of a space discharge device33, the output circuit of which includes the primary of a transformer34. The secondary of the transformer 34 is connected to a pair ofheadphones 35, adapted to be worn by a monitor such as the director ofthe orchestra.

A second phonograph mechanism 4| is pro vided, on the turn table ofwhich is mounted a blank record 42 which has on its upper surface aspiral groove cut by the engraving tool 22 when the engraving mechanism2| was deenergized. Running in the spiral groove of the record 42 is theneedle 43 of a phonograph pick up mechanism 44. This mechanism isconnected to the input circuit of a two-stage amplifier 45 and apush-pull amplifier 46, which are similar in con struction to thosealready described. The output circuit of the push-pull amplifier 45includes the primary of a transformer 41, the secondary of which isconnected across a potentiometer 48, the adjustable contact 49 of whichis connected to the grid of a space discharge device 5|. The outputcircuit of the space discharge device 5| includes the primary of thetransformer 34.

In the operation of the form of the invention shown in the accompanyingfigure, the orchestra leader, for example, leads his orchestra in theusual manner. The music is picked up by the microphone HI and amplifiedby the amplifiers I2, l6 and I8. The greater part of the amplifiedoutput is fed to the engraving mechanism 2|, causing the engraving tool22 to engrave a record of the music on the disc 23, which is later to beused as a master record for the production of the usual phonographrecords.

A small part of the output of the push-pull amplifier l8 passes throughthe secondary |9b to the potentiometer 3|, where any desired amount ispicked up and fed to the device 33, the output of which passes throughthe transformer 34 to the headphones 35.

At the same time, the blank record 42 is being rotated by the mechanism4|, causing the needle 43 to run in the blank groove of the record 42.This needle then picks up the scratch and other ground noises which areamplified by the amplifiers 45 and 46, the output from which passesthrough the potentiometer 48 to the input circuit of the device 5| Theoutput from this device passes through the transformer 34 where it ismixed with the output from the device 33. The combined output thenpasses to the headphones 35, where the orchestra leader hears not onlythe music as being recorded on the disk 23, but also the scratch andground noises of the blank record 42. The adjustable contacts 32 and 49may be so adjusted that the relative intensities of the music andscratch as heard in the headphones 35 corresponds to that in thefinished record which is made from the master record 23.

In this way it is possible for the orchestra leader to hear the scratchnoises together with the music, so that he will not allow the level ofthe music produced by his orchestra to drop below the scratch and groundnoise level. It is accordingly possible to make the records so that thescratch and ground noise will never become objectionable, this beingtaken care of in the making of the records, so that no scratcheliminator will be necessary when the records are being played. Thissystem also has the advantage of allowing the orchestra leader to alwayshear exactly how the music will sound as it is being recorded, and inthis way he can bring out certain groups of instruments, the tones ofwhich may not be amplified as much as other instruments in theorchestra. It also allows him to hear the maximum and minimum soundlevel of the music as recorded, so that he will not allow this to becometoo great or too small for proper recording.

It is obvious that the headphones 35 may also be used by a monitor whocontrols the recording in any convenient manner as, for example, bymeans of potentiometer I4. Furthermore the head phones are merelyillustrative of any suitable sound reproducing device.

Only so much of the circuits have been shown and described as isnecessary to an understanding of the invention. The various details ofthe space discharge amplifiers, auxiliary apparatus and manner of theirconnection are of standard form and will be apparent to a person skilledin the art.

Although one embodiment of this invention has been shown herein, it isto be understood that the invention is not limited to any specificconstruction, but may be embodied in various forms without departingfrom the spirit of the invention or the scope of the appended claims.

What is claimed is:

1. The method of recording sound which com prises energizing a soundreproducing device in accordance with the sound to be recorded and alsosupplying to said sound reproducing device energy orre po ng.ta -mmalrann dsmis of'ar'ecoriwher rsa d dgy jiacansedtolnd ate thereproducing'clfar acteristics ot-tharecord being nTai'fe.

2. The method of recording sound which consists in picking up,amplifying and recording said sound and combining energy proportional tosaid sound with energy derived from the scratch noise of a sound regoiiiahlet, so that the person directing the production of said sound mayhearthe combined efi'ect.

3. In a system for recording sound, a pickup device for picking up soundwaves, an amplifier associated therewith, a recorder for recording theoutput of said amplifier, a scratch producing device, an amplifierassociated therewith, a mixing device for mixing the output of saidscratch amplifier and part of the output of said sound amplifier and asound indicating means operated by the output of said mixing device.

4. A sound recording system comprising a source of sound, a means forrecording said sound, a source of scratch noise, a sound reproducer,means for supplying unrecorded sound energy from said sound source tosaid sound reproducer and means for supplying said scratch noise to saidreproducer.

5. A system for recording music comprising a pick-up device for saidmusic, an amplifier associated therewith, a sound recorder operatedbythe output of said amplifier for recording said music on a soundrecord tablet, a blank sound record tablet, means associated therewithfor picking up the scratch noise of said blank tablet, amplifying meansassociated with said last pickup means, means for combining parts of theoutput energy of both of said amplifying means and sound reproducingmeans for reproducing the combined output of said combining means.

6. A system for recording music comprising a pick-up device for saidmusic, an amplifier associated therewith, a sound recorder operated bythe output of said amplifier for recording said music on a sound recordtablet, a blank sound record tablet, means associated therewith forpicking up the scratch noise of said blank tablet, amplifying meansassociated with said last pickup means for combining parts of the outputenergy of both of said amplifying means, means to adjust the relativeintensity of the parts thus combined and sound reproducing means forreproducing the combined output of said combining means.

7. A sound recording system comprising a pickup means, a recordingmeans, means to translate energy from said pick-up means to saidrecording means, a blank record, means to pick up normal ground noisestherefrom, a sound reproducing means and means to translate to saidsound reproducing means energy from both of said pickup means.

8. A sound recording system comprising a pickup means, a recordingmeans, means to translate energy from said pick-up means to saidrecording means, a blank record, means to pick up normal ground noisestherefrom, a sound reproducing means, means to translate to said soundreproducing means energy from both of said pick-up means, and means toadjust the relative response of said sound reproducing means to energyfrom the respective pick-up means.

9. In a sound recording system, a monitoring circuit for the soundenergy to be recorded and means for arbitrarily introducing ground noiseinto said monitoring circuit.

10. In a sound recording system, a source of sound variations, means forrecording said sound variations, means for monitoring said variationsand means for arbitrarily combining ground noise with part of saidvariations.

11. In a translating system for a sound record, a source of soundvariations, a pick-up device therefor, a monitoring circuit adapted toreceive part of said sound variations from said device and means forarbitrarily introducing ground noise into said monitoring circuit.

12. In a translating system for use with a sound record, a source ofsound energy, a source of background noise, a first and a second channelmeans for applying said sound energy to both of said channels and meansfor applying said background noise to one of said channels.

JOHN HAYS HAMMOND. JR.

